1. Field of the Invention
The present invention relates to power amplifiers and, more particularly, to mechanizations for providing amplitude stabilization for such power amplifiers.
2. Description of the Prior Art
In the prior art, solid state power amplifiers have evidenced characteristic decreases in amplitude over the course of the sustained amplification of an input signal. This characteristic decline in amplitude, which is commonly referred to as amplitude droop, occurs as the result of temperature increases of the amplifier components and the finite capacitance and regulatory capabilities of the amplifier power supply voltage. Amplitude droop in pulsed amplifiers is known to produce undesirable effects. For example, amplitude droop in a driver amplifier provides a variable drive power to the next stage which causes phase modulation and associated spurious outputs. In another example, amplitude droop in the final power amplifier of a transmitter degrades the pulse compression properties of both wide band chirped radars and Barker coded systems.
In the prior art, there has been no way to eliminate the temperature effects in amplifiers due to the self-heating of the amplifier components. Prior art systems directed to the correction of amplitude droop caused by the finite capacitance and regulation of the amplifier supply voltage have involved large amounts of storage capacitance and complicated, stiff power supply systems. Heretofore, feedback type control systems have not generally been used since the amplifiers typically operate in saturated regions where they are unresponsive to output variations in a feedback loop. The presently disclosed amplitude stabilized power amplifier satisfies the need for a power amplifier which is not subject to amplitude droop caused by the self-heating of the amplifier components and also satisfies the need for a power amplifier which is not dependent on large storage capacitance and complicated, unresponsive power supply systems to diminish the impact of the finite capacitance and regulation of the amplifier power supply.